<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Abstract.php 19115 2009-11-20 17:41:25Z matthew $
 */


/**
 * @see Zend_Db
 */
require_once 'Zend/Db.php';

/**
 * @see Zend_Db_Select
 */
require_once 'Zend/Db/Select.php';

/**
 * Class for connecting to SQL databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Db_Adapter_Abstract
{

	/**
	 * User-provided configuration
	 *
	 * @var array
	 */
	protected $_config = array();

	/**
	 * Fetch mode
	 *
	 * @var integer
	 */
	protected $_fetchMode = Zend_Db::FETCH_ASSOC;

	/**
	 * Query profiler object, of type Zend_Db_Profiler
	 * or a subclass of that.
	 *
	 * @var Zend_Db_Profiler
	 */
	protected $_profiler;

	/**
	 * Default class name for a DB statement.
	 *
	 * @var string
	 */
	protected $_defaultStmtClass = 'Zend_Db_Statement';

	/**
	 * Default class name for the profiler object.
	 *
	 * @var string
	 */
	protected $_defaultProfilerClass = 'Zend_Db_Profiler';

	/**
	 * Database connection
	 *
	 * @var object|resource|null
	 */
	protected $_connection = null;

	/**
	 * Specifies the case of column names retrieved in queries
	 * Options
	 * Zend_Db::CASE_NATURAL (default)
	 * Zend_Db::CASE_LOWER
	 * Zend_Db::CASE_UPPER
	 *
	 * @var integer
	 */
	protected $_caseFolding = Zend_Db::CASE_NATURAL;

	/**
	 * Specifies whether the adapter automatically quotes identifiers.
	 * If true, most SQL generated by Zend_Db classes applies
	 * identifier quoting automatically.
	 * If false, developer must quote identifiers themselves
	 * by calling quoteIdentifier().
	 *
	 * @var bool
	 */
	protected $_autoQuoteIdentifiers = true;

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE
	);

	/** Weither or not that object can get serialized
	 *
	 * @var bool
	 */
	protected $_allowSerialization = true;

	/**
	 * Weither or not the database should be reconnected
	 * to that adapter when waking up
	 *
	 * @var bool
	 */
	protected $_autoReconnectOnUnserialize = false;

	/**
	 * Constructor.
	 *
	 * $config is an array of key/value pairs or an instance of Zend_Config
	 * containing configuration options.  These options are common to most adapters:
	 *
	 * dbname         => (string) The name of the database to user
	 * username       => (string) Connect to the database as this username.
	 * password       => (string) Password associated with the username.
	 * host           => (string) What host to connect to, defaults to localhost
	 *
	 * Some options are used on a case-by-case basis by adapters:
	 *
	 * port           => (string) The port of the database
	 * persistent     => (boolean) Whether to use a persistent connection or not, defaults to false
	 * protocol       => (string) The network protocol, defaults to TCPIP
	 * caseFolding    => (int) style of case-alteration used for identifiers
	 *
	 * @param  array|Zend_Config $config An array or instance of Zend_Config having configuration data
	 * @throws Zend_Db_Adapter_Exception
	 */
	public function __construct($config)
	{
		/*
		 * Verify that adapter parameters are in an array.
		 */
		if (!is_array($config)) {
			/*
			 * Convert Zend_Config argument to a plain array.
			 */
			if ($config instanceof Zend_Config) {
				$config = $config->toArray();
			} else {
				/**
				 * @see Zend_Db_Adapter_Exception
				 */
				require_once 'Zend/Db/Adapter/Exception.php';
				throw new Zend_Db_Adapter_Exception('Adapter parameters must be in an array or a Zend_Config object');
			}
		}

		$this->_checkRequiredOptions($config);

		$options = array(
		Zend_Db::CASE_FOLDING           => $this->_caseFolding,
		Zend_Db::AUTO_QUOTE_IDENTIFIERS => $this->_autoQuoteIdentifiers
		);
		$driverOptions = array();

		/*
		 * normalize the config and merge it with the defaults
		 */
		if (array_key_exists('options', $config)) {
			// can't use array_merge() because keys might be integers
			foreach ((array) $config['options'] as $key => $value) {
				$options[$key] = $value;
			}
		}
		if (array_key_exists('driver_options', $config)) {
			if (!empty($config['driver_options'])) {
				// can't use array_merge() because keys might be integers
				foreach ((array) $config['driver_options'] as $key => $value) {
					$driverOptions[$key] = $value;
				}
			}
		}

		if (!isset($config['charset'])) {
			$config['charset'] = null;
		}

		if (!isset($config['persistent'])) {
			$config['persistent'] = false;
		}

		$this->_config = array_merge($this->_config, $config);
		$this->_config['options'] = $options;
		$this->_config['driver_options'] = $driverOptions;


		// obtain the case setting, if there is one
		if (array_key_exists(Zend_Db::CASE_FOLDING, $options)) {
			$case = (int) $options[Zend_Db::CASE_FOLDING];
			switch ($case) {
				case Zend_Db::CASE_LOWER:
				case Zend_Db::CASE_UPPER:
				case Zend_Db::CASE_NATURAL:
					$this->_caseFolding = $case;
					break;
				default:
					/** @see Zend_Db_Adapter_Exception */
					require_once 'Zend/Db/Adapter/Exception.php';
					throw new Zend_Db_Adapter_Exception('Case must be one of the following constants: '
					. 'Zend_Db::CASE_NATURAL, Zend_Db::CASE_LOWER, Zend_Db::CASE_UPPER');
			}
		}

		// obtain quoting property if there is one
		if (array_key_exists(Zend_Db::AUTO_QUOTE_IDENTIFIERS, $options)) {
			$this->_autoQuoteIdentifiers = (bool) $options[Zend_Db::AUTO_QUOTE_IDENTIFIERS];
		}

		// obtain allow serialization property if there is one
		if (array_key_exists(Zend_Db::ALLOW_SERIALIZATION, $options)) {
			$this->_allowSerialization = (bool) $options[Zend_Db::ALLOW_SERIALIZATION];
		}

		// obtain auto reconnect on unserialize property if there is one
		if (array_key_exists(Zend_Db::AUTO_RECONNECT_ON_UNSERIALIZE, $options)) {
			$this->_autoReconnectOnUnserialize = (bool) $options[Zend_Db::AUTO_RECONNECT_ON_UNSERIALIZE];
		}

		// create a profiler object
		$profiler = false;
		if (array_key_exists(Zend_Db::PROFILER, $this->_config)) {
			$profiler = $this->_config[Zend_Db::PROFILER];
			unset($this->_config[Zend_Db::PROFILER]);
		}
		$this->setProfiler($profiler);
	}

	/**
	 * Check for config options that are mandatory.
	 * Throw exceptions if any are missing.
	 *
	 * @param array $config
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _checkRequiredOptions(array $config)
	{
		// we need at least a dbname
		if (! array_key_exists('dbname', $config)) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'dbname' that names the database instance");
		}

		if (! array_key_exists('password', $config)) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'password' for login credentials");
		}

		if (! array_key_exists('username', $config)) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'username' for login credentials");
		}
	}

	/**
	 * Returns the underlying database connection object or resource.
	 * If not presently connected, this initiates the connection.
	 *
	 * @return object|resource|null
	 */
	public function getConnection()
	{
		$this->_connect();
		return $this->_connection;
	}

	/**
	 * Returns the configuration variables in this adapter.
	 *
	 * @return array
	 */
	public function getConfig()
	{
		return $this->_config;
	}

	/**
	 * Set the adapter's profiler object.
	 *
	 * The argument may be a boolean, an associative array, an instance of
	 * Zend_Db_Profiler, or an instance of Zend_Config.
	 *
	 * A boolean argument sets the profiler to enabled if true, or disabled if
	 * false.  The profiler class is the adapter's default profiler class,
	 * Zend_Db_Profiler.
	 *
	 * An instance of Zend_Db_Profiler sets the adapter's instance to that
	 * object.  The profiler is enabled and disabled separately.
	 *
	 * An associative array argument may contain any of the keys 'enabled',
	 * 'class', and 'instance'. The 'enabled' and 'instance' keys correspond to the
	 * boolean and object types documented above. The 'class' key is used to name a
	 * class to use for a custom profiler. The class must be Zend_Db_Profiler or a
	 * subclass. The class is instantiated with no constructor arguments. The 'class'
	 * option is ignored when the 'instance' option is supplied.
	 *
	 * An object of type Zend_Config may contain the properties 'enabled', 'class', and
	 * 'instance', just as if an associative array had been passed instead.
	 *
	 * @param  Zend_Db_Profiler|Zend_Config|array|boolean $profiler
	 * @return Zend_Db_Adapter_Abstract Provides a fluent interface
	 * @throws Zend_Db_Profiler_Exception if the object instance or class specified
	 *         is not Zend_Db_Profiler or an extension of that class.
	 */
	public function setProfiler($profiler)
	{
		$enabled          = null;
		$profilerClass    = $this->_defaultProfilerClass;
		$profilerInstance = null;

		if ($profilerIsObject = is_object($profiler)) {
			if ($profiler instanceof Zend_Db_Profiler) {
				$profilerInstance = $profiler;
			} else if ($profiler instanceof Zend_Config) {
				$profiler = $profiler->toArray();
			} else {
				/**
				 * @see Zend_Db_Profiler_Exception
				 */
				require_once 'Zend/Db/Profiler/Exception.php';
				throw new Zend_Db_Profiler_Exception('Profiler argument must be an instance of either Zend_Db_Profiler'
				. ' or Zend_Config when provided as an object');
			}
		}

		if (is_array($profiler)) {
			if (isset($profiler['enabled'])) {
				$enabled = (bool) $profiler['enabled'];
			}
			if (isset($profiler['class'])) {
				$profilerClass = $profiler['class'];
			}
			if (isset($profiler['instance'])) {
				$profilerInstance = $profiler['instance'];
			}
		} else if (!$profilerIsObject) {
			$enabled = (bool) $profiler;
		}

		if ($profilerInstance === null) {
			if (!class_exists($profilerClass)) {
				require_once 'Zend/Loader.php';
				Zend_Loader::loadClass($profilerClass);
			}
			$profilerInstance = new $profilerClass();
		}

		if (!$profilerInstance instanceof Zend_Db_Profiler) {
			/** @see Zend_Db_Profiler_Exception */
			require_once 'Zend/Db/Profiler/Exception.php';
			throw new Zend_Db_Profiler_Exception('Class ' . get_class($profilerInstance) . ' does not extend '
			. 'Zend_Db_Profiler');
		}

		if (null !== $enabled) {
			$profilerInstance->setEnabled($enabled);
		}

		$this->_profiler = $profilerInstance;

		return $this;
	}


	/**
	 * Returns the profiler for this adapter.
	 *
	 * @return Zend_Db_Profiler
	 */
	public function getProfiler()
	{
		return $this->_profiler;
	}

	/**
	 * Get the default statement class.
	 *
	 * @return string
	 */
	public function getStatementClass()
	{
		return $this->_defaultStmtClass;
	}

	/**
	 * Set the default statement class.
	 *
	 * @return Zend_Db_Adapter_Abstract Fluent interface
	 */
	public function setStatementClass($class)
	{
		$this->_defaultStmtClass = $class;
		return $this;
	}

	/**
	 * Prepares and executes an SQL statement with bound data.
	 *
	 * @param  mixed  $sql  The SQL statement with placeholders.
	 *                      May be a string or Zend_Db_Select.
	 * @param  mixed  $bind An array of data to bind to the placeholders.
	 * @return Zend_Db_Statement_Interface
	 */
	public function query($sql, $bind = array())
	{
		// connect to the database if needed
		$this->_connect();

		// is the $sql a Zend_Db_Select object?
		if ($sql instanceof Zend_Db_Select) {
			if (empty($bind)) {
				$bind = $sql->getBind();
			}

			$sql = $sql->assemble();
		}

		// make sure $bind to an array;
		// don't use (array) typecasting because
		// because $bind may be a Zend_Db_Expr object
		if (!is_array($bind)) {
			$bind = array($bind);
		}

		// prepare and execute the statement with profiling
		$stmt = $this->prepare($sql);
		$stmt->execute($bind);

		// return the results embedded in the prepared statement object
		$stmt->setFetchMode($this->_fetchMode);
		return $stmt;
	}

	/**
	 * Leave autocommit mode and begin a transaction.
	 *
	 * @return Zend_Db_Adapter_Abstract
	 */
	public function beginTransaction()
	{
		$this->_connect();
		$q = $this->_profiler->queryStart('begin', Zend_Db_Profiler::TRANSACTION);
		$this->_beginTransaction();
		$this->_profiler->queryEnd($q);
		return $this;
	}

	/**
	 * Commit a transaction and return to autocommit mode.
	 *
	 * @return Zend_Db_Adapter_Abstract
	 */
	public function commit()
	{
		$this->_connect();
		$q = $this->_profiler->queryStart('commit', Zend_Db_Profiler::TRANSACTION);
		$this->_commit();
		$this->_profiler->queryEnd($q);
		return $this;
	}

	/**
	 * Roll back a transaction and return to autocommit mode.
	 *
	 * @return Zend_Db_Adapter_Abstract
	 */
	public function rollBack()
	{
		$this->_connect();
		$q = $this->_profiler->queryStart('rollback', Zend_Db_Profiler::TRANSACTION);
		$this->_rollBack();
		$this->_profiler->queryEnd($q);
		return $this;
	}

	/**
	 * Inserts a table row with specified data.
	 *
	 * @param mixed $table The table to insert data into.
	 * @param array $bind Column-value pairs.
	 * @return int The number of affected rows.
	 */
	public function insert($table, array $bind)
	{
		// extract and quote col names from the array keys
		$cols = array();
		$vals = array();
		foreach ($bind as $col => $val) {
			$cols[] = $this->quoteIdentifier($col, true);
			if ($val instanceof Zend_Db_Expr) {
				$vals[] = $val->__toString();
				unset($bind[$col]);
			} else {
				$vals[] = '?';
			}
		}

		// build the statement
		$sql = "INSERT INTO "
		. $this->quoteIdentifier($table, true)
		. ' (' . implode(', ', $cols) . ') '
		. 'VALUES (' . implode(', ', $vals) . ')';

		// execute the statement and return the number of affected rows
		$stmt = $this->query($sql, array_values($bind));
		$result = $stmt->rowCount();
		return $result;
	}

	/**
	 * Updates table rows with specified data based on a WHERE clause.
	 *
	 * @param  mixed        $table The table to update.
	 * @param  array        $bind  Column-value pairs.
	 * @param  mixed        $where UPDATE WHERE clause(s).
	 * @return int          The number of affected rows.
	 */
	public function update($table, array $bind, $where = '')
	{
		/**
		 * Build "col = ?" pairs for the statement,
		 * except for Zend_Db_Expr which is treated literally.
		 */
		$set = array();
		$i = 0;
		foreach ($bind as $col => $val) {
			if ($val instanceof Zend_Db_Expr) {
				$val = $val->__toString();
				unset($bind[$col]);
			} else {
				if ($this->supportsParameters('positional')) {
					$val = '?';
				} else {
					if ($this->supportsParameters('named')) {
						unset($bind[$col]);
						$bind[':'.$col.$i] = $val;
						$val = ':'.$col.$i;
						$i++;
					} else {
						/** @see Zend_Db_Adapter_Exception */
						require_once 'Zend/Db/Adapter/Exception.php';
						throw new Zend_Db_Adapter_Exception(get_class($this) ." doesn't support positional or named binding");
					}
				}
			}
			$set[] = $this->quoteIdentifier($col, true) . ' = ' . $val;
		}

		$where = $this->_whereExpr($where);

		/**
		 * Build the UPDATE statement
		 */
		$sql = "UPDATE "
		. $this->quoteIdentifier($table, true)
		. ' SET ' . implode(', ', $set)
		. (($where) ? " WHERE $where" : '');

		/**
		 * Execute the statement and return the number of affected rows
		 */
		if ($this->supportsParameters('positional')) {
			$stmt = $this->query($sql, array_values($bind));
		} else {
			$stmt = $this->query($sql, $bind);
		}
		$result = $stmt->rowCount();
		return $result;
	}

	/**
	 * Deletes table rows based on a WHERE clause.
	 *
	 * @param  mixed        $table The table to update.
	 * @param  mixed        $where DELETE WHERE clause(s).
	 * @return int          The number of affected rows.
	 */
	public function delete($table, $where = '')
	{
		$where = $this->_whereExpr($where);

		/**
		 * Build the DELETE statement
		 */
		$sql = "DELETE FROM "
		. $this->quoteIdentifier($table, true)
		. (($where) ? " WHERE $where" : '');

		/**
		 * Execute the statement and return the number of affected rows
		 */
		$stmt = $this->query($sql);
		$result = $stmt->rowCount();
		return $result;
	}

	/**
	 * Convert an array, string, or Zend_Db_Expr object
	 * into a string to put in a WHERE clause.
	 *
	 * @param mixed $where
	 * @return string
	 */
	protected function _whereExpr($where)
	{
		if (empty($where)) {
			return $where;
		}
		if (!is_array($where)) {
			$where = array($where);
		}
		foreach ($where as $cond => &$term) {
			// is $cond an int? (i.e. Not a condition)
			if (is_int($cond)) {
				// $term is the full condition
				if ($term instanceof Zend_Db_Expr) {
					$term = $term->__toString();
				}
			} else {
				// $cond is the condition with placeholder,
				// and $term is quoted into the condition
				$term = $this->quoteInto($cond, $term);
			}
			$term = '(' . $term . ')';
		}

		$where = implode(' AND ', $where);
		return $where;
	}

	/**
	 * Creates and returns a new Zend_Db_Select object for this adapter.
	 *
	 * @return Zend_Db_Select
	 */
	public function select()
	{
		return new Zend_Db_Select($this);
	}

	/**
	 * Get the fetch mode.
	 *
	 * @return int
	 */
	public function getFetchMode()
	{
		return $this->_fetchMode;
	}

	/**
	 * Fetches all SQL result rows as a sequential array.
	 * Uses the current fetchMode for the adapter.
	 *
	 * @param string|Zend_Db_Select $sql  An SQL SELECT statement.
	 * @param mixed                 $bind Data to bind into SELECT placeholders.
	 * @param mixed                 $fetchMode Override current fetch mode.
	 * @return array
	 */
	public function fetchAll($sql, $bind = array(), $fetchMode = null)
	{
		if ($fetchMode === null) {
			$fetchMode = $this->_fetchMode;
		}
		$stmt = $this->query($sql, $bind);
		$result = $stmt->fetchAll($fetchMode);
		return $result;
	}

	/**
	 * Fetches the first row of the SQL result.
	 * Uses the current fetchMode for the adapter.
	 *
	 * @param string|Zend_Db_Select $sql An SQL SELECT statement.
	 * @param mixed $bind Data to bind into SELECT placeholders.
	 * @param mixed                 $fetchMode Override current fetch mode.
	 * @return array
	 */
	public function fetchRow($sql, $bind = array(), $fetchMode = null)
	{
		if ($fetchMode === null) {
			$fetchMode = $this->_fetchMode;
		}
		$stmt = $this->query($sql, $bind);
		$result = $stmt->fetch($fetchMode);
		return $result;
	}

	/**
	 * Fetches all SQL result rows as an associative array.
	 *
	 * The first column is the key, the entire row array is the
	 * value.  You should construct the query to be sure that
	 * the first column contains unique values, or else
	 * rows with duplicate values in the first column will
	 * overwrite previous data.
	 *
	 * @param string|Zend_Db_Select $sql An SQL SELECT statement.
	 * @param mixed $bind Data to bind into SELECT placeholders.
	 * @return array
	 */
	public function fetchAssoc($sql, $bind = array())
	{
		$stmt = $this->query($sql, $bind);
		$data = array();
		while ($row = $stmt->fetch(Zend_Db::FETCH_ASSOC)) {
			$tmp = array_values(array_slice($row, 0, 1));
			$data[$tmp[0]] = $row;
		}
		return $data;
	}

	/**
	 * Fetches the first column of all SQL result rows as an array.
	 *
	 * The first column in each row is used as the array key.
	 *
	 * @param string|Zend_Db_Select $sql An SQL SELECT statement.
	 * @param mixed $bind Data to bind into SELECT placeholders.
	 * @return array
	 */
	public function fetchCol($sql, $bind = array())
	{
		$stmt = $this->query($sql, $bind);
		$result = $stmt->fetchAll(Zend_Db::FETCH_COLUMN, 0);
		return $result;
	}

	/**
	 * Fetches all SQL result rows as an array of key-value pairs.
	 *
	 * The first column is the key, the second column is the
	 * value.
	 *
	 * @param string|Zend_Db_Select $sql An SQL SELECT statement.
	 * @param mixed $bind Data to bind into SELECT placeholders.
	 * @return array
	 */
	public function fetchPairs($sql, $bind = array())
	{
		$stmt = $this->query($sql, $bind);
		$data = array();
		while ($row = $stmt->fetch(Zend_Db::FETCH_NUM)) {
			$data[$row[0]] = $row[1];
		}
		return $data;
	}

	/**
	 * Fetches the first column of the first row of the SQL result.
	 *
	 * @param string|Zend_Db_Select $sql An SQL SELECT statement.
	 * @param mixed $bind Data to bind into SELECT placeholders.
	 * @return string
	 */
	public function fetchOne($sql, $bind = array())
	{
		$stmt = $this->query($sql, $bind);
		$result = $stmt->fetchColumn(0);
		return $result;
	}

	/**
	 * Quote a raw string.
	 *
	 * @param string $value     Raw string
	 * @return string           Quoted string
	 */
	protected function _quote($value)
	{
		if (is_int($value)) {
			return $value;
		} elseif (is_float($value)) {
			return sprintf('%F', $value);
		}
		return "'" . addcslashes($value, "\000\n\r\\'\"\032") . "'";
	}

	/**
	 * Safely quotes a value for an SQL statement.
	 *
	 * If an array is passed as the value, the array values are quoted
	 * and then returned as a comma-separated string.
	 *
	 * @param mixed $value The value to quote.
	 * @param mixed $type  OPTIONAL the SQL datatype name, or constant, or null.
	 * @return mixed An SQL-safe quoted value (or string of separated values).
	 */
	public function quote($value, $type = null)
	{
		$this->_connect();

		if ($value instanceof Zend_Db_Select) {
			return '(' . $value->assemble() . ')';
		}

		if ($value instanceof Zend_Db_Expr) {
			return $value->__toString();
		}

		if (is_array($value)) {
			foreach ($value as &$val) {
				$val = $this->quote($val, $type);
			}
			return implode(', ', $value);
		}

		if ($type !== null && array_key_exists($type = strtoupper($type), $this->_numericDataTypes)) {
			$quotedValue = '0';
			switch ($this->_numericDataTypes[$type]) {
				case Zend_Db::INT_TYPE: // 32-bit integer
					$quotedValue = (string) intval($value);
					break;
				case Zend_Db::BIGINT_TYPE: // 64-bit integer
					// ANSI SQL-style hex literals (e.g. x'[\dA-F]+')
					// are not supported here, because these are string
					// literals, not numeric literals.
					if (preg_match('/^(
                          [+-]?                  # optional sign
                          (?:
                            0[Xx][\da-fA-F]+     # ODBC-style hexadecimal
                            |\d+                 # decimal or octal, or MySQL ZEROFILL decimal
                            (?:[eE][+-]?\d+)?    # optional exponent on decimals or octals
                          )
                        )/x',
					(string) $value, $matches)) {
						$quotedValue = $matches[1];
					}
					break;
				case Zend_Db::FLOAT_TYPE: // float or decimal
					$quotedValue = sprintf('%F', $value);
			}
			return $quotedValue;
		}

		return $this->_quote($value);
	}

	/**
	 * Quotes a value and places into a piece of text at a placeholder.
	 *
	 * The placeholder is a question-mark; all placeholders will be replaced
	 * with the quoted value.   For example:
	 *
	 * <code>
	 * $text = "WHERE date < ?";
	 * $date = "2005-01-02";
	 * $safe = $sql->quoteInto($text, $date);
	 * // $safe = "WHERE date < '2005-01-02'"
	 * </code>
	 *
	 * @param string  $text  The text with a placeholder.
	 * @param mixed   $value The value to quote.
	 * @param string  $type  OPTIONAL SQL datatype
	 * @param integer $count OPTIONAL count of placeholders to replace
	 * @return string An SQL-safe quoted value placed into the original text.
	 */
	public function quoteInto($text, $value, $type = null, $count = null)
	{
		if ($count === null) {
			return str_replace('?', $this->quote($value, $type), $text);
		} else {
			while ($count > 0) {
				if (strpos($text, '?') !== false) {
					$text = substr_replace($text, $this->quote($value, $type), strpos($text, '?'), 1);
				}
				--$count;
			}
			return $text;
		}
	}

	/**
	 * Quotes an identifier.
	 *
	 * Accepts a string representing a qualified indentifier. For Example:
	 * <code>
	 * $adapter->quoteIdentifier('myschema.mytable')
	 * </code>
	 * Returns: "myschema"."mytable"
	 *
	 * Or, an array of one or more identifiers that may form a qualified identifier:
	 * <code>
	 * $adapter->quoteIdentifier(array('myschema','my.table'))
	 * </code>
	 * Returns: "myschema"."my.table"
	 *
	 * The actual quote character surrounding the identifiers may vary depending on
	 * the adapter.
	 *
	 * @param string|array|Zend_Db_Expr $ident The identifier.
	 * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
	 * @return string The quoted identifier.
	 */
	public function quoteIdentifier($ident, $auto=false)
	{
		return $this->_quoteIdentifierAs($ident, null, $auto);
	}

	/**
	 * Quote a column identifier and alias.
	 *
	 * @param string|array|Zend_Db_Expr $ident The identifier or expression.
	 * @param string $alias An alias for the column.
	 * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
	 * @return string The quoted identifier and alias.
	 */
	public function quoteColumnAs($ident, $alias, $auto=false)
	{
		return $this->_quoteIdentifierAs($ident, $alias, $auto);
	}

	/**
	 * Quote a table identifier and alias.
	 *
	 * @param string|array|Zend_Db_Expr $ident The identifier or expression.
	 * @param string $alias An alias for the table.
	 * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
	 * @return string The quoted identifier and alias.
	 */
	public function quoteTableAs($ident, $alias = null, $auto = false)
	{
		return $this->_quoteIdentifierAs($ident, $alias, $auto);
	}

	/**
	 * Quote an identifier and an optional alias.
	 *
	 * @param string|array|Zend_Db_Expr $ident The identifier or expression.
	 * @param string $alias An optional alias.
	 * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
	 * @param string $as The string to add between the identifier/expression and the alias.
	 * @return string The quoted identifier and alias.
	 */
	protected function _quoteIdentifierAs($ident, $alias = null, $auto = false, $as = ' AS ')
	{
		if ($ident instanceof Zend_Db_Expr) {
			$quoted = $ident->__toString();
		} elseif ($ident instanceof Zend_Db_Select) {
			$quoted = '(' . $ident->assemble() . ')';
		} else {
			if (is_string($ident)) {
				$ident = explode('.', $ident);
			}
			if (is_array($ident)) {
				$segments = array();
				foreach ($ident as $segment) {
					if ($segment instanceof Zend_Db_Expr) {
						$segments[] = $segment->__toString();
					} else {
						$segments[] = $this->_quoteIdentifier($segment, $auto);
					}
				}
				if ($alias !== null && end($ident) == $alias) {
					$alias = null;
				}
				$quoted = implode('.', $segments);
			} else {
				$quoted = $this->_quoteIdentifier($ident, $auto);
			}
		}
		if ($alias !== null) {
			$quoted .= $as . $this->_quoteIdentifier($alias, $auto);
		}
		return $quoted;
	}

	/**
	 * Quote an identifier.
	 *
	 * @param  string $value The identifier or expression.
	 * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
	 * @return string        The quoted identifier and alias.
	 */
	protected function _quoteIdentifier($value, $auto=false)
	{
		if ($auto === false || $this->_autoQuoteIdentifiers === true) {
			$q = $this->getQuoteIdentifierSymbol();
			return ($q . str_replace("$q", "$q$q", $value) . $q);
		}
		return $value;
	}

	/**
	 * Returns the symbol the adapter uses for delimited identifiers.
	 *
	 * @return string
	 */
	public function getQuoteIdentifierSymbol()
	{
		return '"';
	}

	/**
	 * Return the most recent value from the specified sequence in the database.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function lastSequenceId($sequenceName)
	{
		return null;
	}

	/**
	 * Generate a new value from the specified sequence in the database, and return it.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function nextSequenceId($sequenceName)
	{
		return null;
	}

	/**
	 * Helper method to change the case of the strings used
	 * when returning result sets in FETCH_ASSOC and FETCH_BOTH
	 * modes.
	 *
	 * This is not intended to be used by application code,
	 * but the method must be public so the Statement class
	 * can invoke it.
	 *
	 * @param string $key
	 * @return string
	 */
	public function foldCase($key)
	{
		switch ($this->_caseFolding) {
			case Zend_Db::CASE_LOWER:
				$value = strtolower((string) $key);
				break;
			case Zend_Db::CASE_UPPER:
				$value = strtoupper((string) $key);
				break;
			case Zend_Db::CASE_NATURAL:
			default:
				$value = (string) $key;
		}
		return $value;
	}

	/**
	 * called when object is getting serialized
	 * This disconnects the DB object that cant be serialized
	 *
	 * @throws Zend_Db_Adapter_Exception
	 * @return array
	 */
	public function __sleep()
	{
		if ($this->_allowSerialization == false) {
			/** @see Zend_Db_Adapter_Exception */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception(get_class($this) ." is not allowed to be serialized");
		}
		$this->_connection = false;
		return array_keys(array_diff_key(get_object_vars($this), array('_connection'=>false)));
	}

	/**
	 * called when object is getting unserialized
	 *
	 * @return void
	 */
	public function __wakeup()
	{
		if ($this->_autoReconnectOnUnserialize == true) {
			$this->getConnection();
		}
	}

	/**
	 * Abstract Methods
	 */

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	abstract public function listTables();

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME => string; name of database or schema
	 * TABLE_NAME  => string;
	 * COLUMN_NAME => string; column name
	 * COLUMN_POSITION => number; ordinal position of column in table
	 * DATA_TYPE   => string; SQL datatype name of column
	 * DEFAULT     => string; default expression of column, null if none
	 * NULLABLE    => boolean; true if column can have nulls
	 * LENGTH      => number; length of CHAR/VARCHAR
	 * SCALE       => number; scale of NUMERIC/DECIMAL
	 * PRECISION   => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED    => boolean; unsigned property of an integer type
	 * PRIMARY     => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 *
	 * @param string $tableName
	 * @param string $schemaName OPTIONAL
	 * @return array
	 */
	abstract public function describeTable($tableName, $schemaName = null);

	/**
	 * Creates a connection to the database.
	 *
	 * @return void
	 */
	abstract protected function _connect();

	/**
	 * Test if a connection is active
	 *
	 * @return boolean
	 */
	abstract public function isConnected();

	/**
	 * Force the connection to close.
	 *
	 * @return void
	 */
	abstract public function closeConnection();

	/**
	 * Prepare a statement and return a PDOStatement-like object.
	 *
	 * @param string|Zend_Db_Select $sql SQL query
	 * @return Zend_Db_Statement|PDOStatement
	 */
	abstract public function prepare($sql);

	/**
	 * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
	 *
	 * As a convention, on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
	 * from the arguments and returns the last id generated by that sequence.
	 * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
	 * returns the last value generated for such a column, and the table name
	 * argument is disregarded.
	 *
	 * @param string $tableName   OPTIONAL Name of table.
	 * @param string $primaryKey  OPTIONAL Name of primary key column.
	 * @return string
	 */
	abstract public function lastInsertId($tableName = null, $primaryKey = null);

	/**
	 * Begin a transaction.
	 */
	abstract protected function _beginTransaction();

	/**
	 * Commit a transaction.
	 */
	abstract protected function _commit();

	/**
	 * Roll-back a transaction.
	 */
	abstract protected function _rollBack();

	/**
	 * Set the fetch mode.
	 *
	 * @param integer $mode
	 * @return void
	 * @throws Zend_Db_Adapter_Exception
	 */
	abstract public function setFetchMode($mode);

	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param mixed $sql
	 * @param integer $count
	 * @param integer $offset
	 * @return string
	 */
	abstract public function limit($sql, $count, $offset = 0);

	/**
	 * Check if the adapter supports real SQL parameters.
	 *
	 * @param string $type 'positional' or 'named'
	 * @return bool
	 */
	abstract public function supportsParameters($type);

	/**
	 * Retrieve server version in PHP style
	 *
	 * @return string
	 */
	abstract public function getServerVersion();
}
